Biology subjects

De Wever, O.

Publications and source records attributed to De Wever, O..

5 recordsLinked to original sources

bioRxiv2026

Label-Free Monitoring of Cancer-associated Fibroblast Activation using NADH Fluorescence Lifetime Imaging

Cancer-associated fibroblasts (CAFs) are key regulators of tumor progression, yet their activation state is commonly assessed using static, endpoint assays that do not allow dynamic analysis in living cells. Although CAF activation is accompanied by pronounced metabolic remodeling, label-free approaches that exploit these changes for real-time monitoring remain limited. Here, we demonstrate that NADH fluorescence lifetime imaging microscopy (FLIM) provides a non-invasive readout of this process. CAFs activated with transforming growth factor beta (TGF-{beta}) exhibit a reproducible shift toward longer NADH fluorescence lifetimes compared to non-activated cells, consistent with changes in the relative contributions of free and protein-bound NADH. By combining live-cell FLIM with -smooth muscle actin staining in the same cells, we directly link metabolic signatures to cellular activation state. We further demonstrate the potential of this approach to dynamically monitor CAF activation in live, migrating cells. Together, these results establish NADH fluorescence lifetime imaging as a label-free metabolic approach for monitoring CAF activation dynamics, complementing conventional marker-based methods and enabling continuous monitoring of tumor-stroma interactions.

biochemistry↗

bioRxiv2021

Performance of RNA purification kits and blood collection tubes in the Extracellular RNA Quality Control (exRNAQC) study

The use of blood-based extracellular RNA (cell-free RNA; exRNA) as clinical biomarker requires the implementation of a validated procedure for sample collection, processing, and profiling. So far, no study has systematically addressed the pre-analytical variables affecting transcriptome analysis of exRNAs. In the exRNAQC study, we evaluated ten blood collection tubes, three time intervals between blood draw and downstream processing, and eight RNA purification methods using the supplier-specified minimum and maximum biofluid input volumes. The impact of these pre-analytics on deep transcriptome profiling of both small and messenger RNA from healthy donors plasma or serum was assessed for each pre-analytical variable separately and for interactions between a selected set of pre-analytics, resulting in 456 extracellular transcriptomes. Making use of 189 synthetic spike-in RNAs, the processing and analysis workflow was controlled. When comparing blood collection tubes, so-called preservation tubes do not stabilize exRNA well, and result in variable RNA concentration and sensitivity (i.e., the number of detected RNAs) over time, as well as compromised reproducibility. We also document large differences in RNA purification kit performance in terms of sensitivity, reproducibility, and observed transcriptome complexity, and demonstrate interactions between specific blood collection tubes, purification kits and time intervals. Our results are summarized in 11 performance metrics that enable an informed selection of the most optimal sample processing workflow for a given experiment. In conclusion, we put forward robust quality control metrics for exRNA quantification methods with validated standard operating procedures (SOPs), representing paramount groundwork for future exRNA-based precision medicine applications.

genomics↗

bioRxiv2020

The quorum sensing peptide EntF* promotes colorectal cancer metastasis in mice: a new factor in the microbiome-host interaction.

BackgroundColorectal cancer, one of the most common malignancies worldwide, is associated with a high mortality rate, mainly caused by metastasis. Comparative metagenome-wide analyses between healthy individuals and cancer patients suggest a role for the human intestinal microbiota. Nevertheless, which microbial molecules are involved in this communication is largely unknown, with current studies mainly focusing on short chain fatty acids and amino acid metabolites as potential mediators. However, quorum sensing peptides are not yet considered in this microbiome-host interaction: their in vivo presence nor any in vivo host-effect have been reported. ResultsFor the first time, we showed that a quorum sensing peptide metabolite, EntF* produced by intestinal microbiota (E. faecium), is present in the blood circulation of mice. Moreover, it significantly promotes colorectal cancer metastasis in vivo, with metastatic lesions found in both liver and lung tissues, using an orthotopic mice model evaluating bioluminescence as well as macroscopic and microscopic presence of metastatic tumour nodules. In vitro tests on E-cadherin expression levels thereby indicated that the first, second, sixth and tenth amino acid of EntF* were critical for the epithelial-mesenchymal transition (EMT) effect, responsible for tumour metastasis. ConclusionThis paper adds a new group of molecules, the quorum sensing peptides, as an additional causative factor explaining the microbiome-host interaction. The presence of a selected quorum sensing peptide (metabolite) in the mouse was proven for the first time and its in vivo effect on colorectal metastasis was demonstrated. We anticipate our in vivo results to be a starting point for broader microbiome-health investigations, not only limited to colorectal cancer metastasis, but also for developing novel bio-therapeutics in other disease areas, giving due attention to the QSP produced by the microbiome.

molecular biology↗

bioRxiv2019

Establishment and characterization of a cell line and patient-derived xenograft (PDX) from peritoneal metastasis of low-grade serous ovarian carcinoma

Peritoneal spread indicates poor prognosis in patients with serous ovarian carcinoma (SOC) and is generally treated by surgical cytoreduction and chemotherapy. Novel treatment options are urgently needed to improve patient outcome. Clinically relevant cell lines and patient-derived xenograft (PDX) models are of critical importance to therapeutic regimen evaluation. Here, a PDX model was established by orthotopic engraftment, subperitoneal tumor slurry injection, of low-grade SOC resulting in an early-stage transplantable peritoneal metastasis (PM)-PDX model. Histology confirmed the micropapillary and cribriform growth pattern with intraluminal tumor budding and positivity for PAX8 and WT1. PM-PDX dissociated cells show an epithelial morphotype with a 42h doubling time and 40% colony forming efficiency, they are insensitive to estrogen signaling, low sensitive to platinum derivatives and highly sensitive to paclitaxel (IC50: 6.3 {+/-} 2.2 nM, mean {+/-} SE). The patient primary tumor, PM, PM-PDX and derived cell line all show a KRAS c.35G>T (p.(Gly12Val)) mutation and show sensitivity to the MEK inhibitor trametinib in vitro (IC50: 7.2 {+/-} 0.5 nM, mean {+/-} SE) and in the PM mouse model. These preclinical models closely reflecting patient tumors are useful to further elucidate LGSOC disease progression, therapy response and resistance mechanisms.

cancer biology↗

bioRxiv2017

Laminin α1 orchestrates VEGFA functions in the ecosystem of colorectal carcinoma

Tumor stroma remodeling is a key feature of malignant tumors and can promote cancer progression. Laminins are major constituents of basement membranes that physically separate the epithelium from the underlying stroma. By employing mouse models expressing high and low levels of the laminin 1 chain (LM1), we highlighted its implication in a tumorstroma crosstalk, thus leading to increased colon tumor incidence, angiogenesis and tumor growth. The underlying mechanism involves attraction of carcinoma-associated fibroblasts by LM1, VEGFA expression triggered by the complex integrin 2{beta}1-CXCR4 and binding of VEGFA to LM-111, which in turn promotes angiogenesis, tumor cell survival and proliferation. A gene signature comprising LAMA1, ITGB1, ITGA2, CXCR4 and VEGFA has negative predictive value in colon cancer. Together, this information opens novel opportunities for diagnosis and anti-cancer targeting.

cancer biology↗